198777641 has 2 divisors, whose sum is σ = 198777642. Its totient is φ = 198777640.

The previous prime is 198777559. The next prime is 198777643. The reversal of 198777641 is 146777891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111915241 + 86862400 = 10579^2 + 9320^2 .

It is a cyclic number.

It is not a de Polignac number, because 198777641 - 2¹⁸ = 198515497 is a prime.

It is a Sophie Germain prime.

Together with 198777643, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 198777641.

It is not a weakly prime, because it can be changed into another prime (198777643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99388820 + 99388821.

It is an arithmetic number, because the mean of its divisors is an integer number (99388821).

Almost surely, 2^198777641 is an apocalyptic number.

It is an amenable number.

198777641 is a deficient number, since it is larger than the sum of its proper divisors (1).

198777641 is an equidigital number, since it uses as much as digits as its factorization.

198777641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 592704, while the sum is 50.

The square root of 198777641 is about 14098.8524710347. The cubic root of 198777641 is about 583.6097123708.

The spelling of 198777641 in words is "one hundred ninety-eight million, seven hundred seventy-seven thousand, six hundred forty-one".